木材硬度.docx

原文地址：木材简卡硬度janka作者：rbt01janka硬度主要测试表面硬度而非端面硬度。janka单位是磅，转化为牛顿（pa压强标准单位,n/cm2）要乘以4.44。2000: 硬3000: 甚硬4000: 超硬5000: 极硬我们的紫檀2940，大红酸枝2260，属于硬类，上面还有3层超硬类。超级硬木族schinoposis , 辛诺普西guaiacum, 怪爱可，愈疮木，中国用名为铁梨木。属疾藜科acacia, 爱可夏，阿拉伯树胶；刺槐；金合欢属xanthostemon ，仙草斯泰姆，蒲桃名木族：mahogany 桃花心swartzia, 铁木豆diospyros, 柿子树属caesalpinia, 苏木属世界硬木排名前25：1 - buloke australian allocasuarina luehmannii 5060 - specific gravity 1.11 异木麻黄属5060 pounds force lbf - 2294 kilograms force kgf - 22.5 kilonewtons kn - 22500 newtons n2 - quebracho colorado - soto schinopsis brasiliensis 4800 - specific gravity 1.283 - quebracho colorado - paag schinopsis lorentzii 4700 - specific gravity 1.225 - belah casuarina cristata 4500 - specific gravity 1.155 - lignum vitae - tree of life guaiacum officinale 4500 - specific gravity 1.356 - lignum vitae philippine xanthostemon verdugonianus 4450 - specific gravity 1.227 - mgurure combretum schumannii 4430 - specific gravity 1.08，风车子属8 - bauhinia red lysiphyllum carronii 4400 - specific gravity 1.39， 豆科植物9 - tubi - blackwood solomon - ebony queen xanthostemon melanoxylon 4370 - specific gravity 1.23110 - knob thorn acacia nigrescens 4290 - specific gravity 1.2111 gidgee acacia cambagei 4270 - specific gravity 1.3512 gidgee georgina acacia georginae 4270 - specific gravity 1.3313 tiga tristaniopsis decorticata 4260 - specific gravity 1.05314 lignum vitae - holywood guaiacum sanctum 4250 - specific gravity 1.31 - hardest wood in united states15 quebracho colorado - barauna schinopsis balansae 4250 - specific gravity 1.2216 lignum vitae maracaibo bulnesia arborea 4200 - specific gravity 1.25 维拉木，绿檀17 lignum vitae paraguayan bulnesia sarmientoi 4200 - specific gravity 1.1918 snakewood australian acacia xiphophylla 4150 - specific gravity 1.321 蛇桑19 wattle lakewood acacia enervia 4150 - specific gravity 1.3220 spearwood brown acacia rhodoxylon 4100 - specific gravity 1.2821 gimlet eucalyptus salubris 4090 - specific gravity 1.225，桉树；桉属植物22 oak black australian casuarina pauper 4080 - specific gravity 1.29，木麻黄23 blackwood african dalbergia melanoxylon 4050 - specific gravity 1.28 南非黑黄檀24 wattle acacia excelsa 4050 - specific gravity 1.1525 - lignum vitae texan guaiacum angustifolium 4030 - specific gravity 1.276=the janka hardness scale was invented in 1906 by gabriel janka 1864 - 1932. he was an austrian wood researcher. in 1906 at the age of 42 he wrote the 40 page book, die harte des holzes translated is the hardness of the wood.the janka hardness test measures how hard wood/lumber/timber is. the higher the number the harder the wood is. it is an adaptation of the brinell hardness test for metals.it is probably the best way to determine how durable a particular wood species is. how easy or difficult it will be to dent, ding, mar or scratch. this is extremely important if you are using solid wood for certain applications such as interior flooring, exterior decking, porch flooring, stair treads, stair landings, tabletops, desktops, kitchen countertops and workbench countertops.it is very important to percussion instrument makers drums etcetera, woodwind instrument makers flutes etcetera and stringed instrument makers luthiers guitars etcetera because a certain hardness produces a particular distintive tone, the harder the wood the sharper the tone that it will produce. also with luthiers certain parts such as necks and bridges are made from a certain hardness of wood.it is also a very good indicator of how easy or difficult a particular wood species will be to nail, screw, saw, plane, route, carve and work in general.the results of the original test were indicated in units of pressure required to drive in a steel ball with a diameter of 11.28 millimeters 0.444 inches into the wood to half its diameter. this procedure was chosen so that the result would leave an indentation of exactly 100 square millimeters 0.16 square inches in size. when the american society for testing and materials astm standardized the test in 1927 it called for the results to be indicated in units of force.now in the english measurement system, the result is indicated in pounds of force lbf, in the metric measurement system, the result is indicated in kilograms of force kgf) and in australia the result is indicated in newtons n or kilonewtons kn.the hardness of wood/lumber/timber usually varies with the direction of the wood grain. when testing is done on the tangential and radial surface of a piece of wood with the force applied perpendicular to the grain, the test is of side hardness. all janka hardnesses listed on this website are of side hardness.testing is done on wood from the trunk of the tree and is almost always the heartwood. with heartwood there are a handful of exceptions. one that comes to mind is balsa ochroma pyramidale. balsa is always milled from sapwood.the standard sample as indicated in astm d 1043 is to be at 12% moisture content, be clear no knots, a solid block of wood having the dimensions of at least 2 x 2 x 6 long and the rate of loading will be machine set at 1/4 per minute.two indentations are made on the tangential surface and two indentations on the radial surface. the four indentations are then added together and divided by 4 to get the average value of the force, with the result being declared as the side hardness.when testing is done on a piece of wood with the force applied to the end grain surface, the test is of end hardness. the end hardness of wood/lumber/timber will almost always be higher harder than its side hardness. there are exceptions. examples would be,beefwood manilkara bidentatajanka hardness end 2650janka hardness side 3190koroboreli peltogyne pubescensjanka hardness end 3350janka hardness side 3640wacapou vouacapoua americanajanka hardness end 1600janka hardness side 1730most wood/lumber/timber species will deviate in hardness but not by much more than plus or minus 10% of the chart numbers below from one piece of wood/lumber/timber to another or wood coming from two different geographical locations. with geographical locations there are exceptions. examples would be,ebony macassar indonesian grown diospyros celebica 3220 - specific gravity 1.15ebony macassar australian grown diospyros celebica 3650 - specific gravity 1.296olivewood mediterranean grown olea europaea 2740 - specific gravity .95olivewood southeast african grown olea europaea 3180 - specific gravity 1.15also the wood/lumber/timber around knots, having interlocked grain, at less than 12% moisture content and burl wood will be harder than the chart numbers below which are of average side hardness with the wood at 12% moisture content.notesnote 1:trees can be classed or grouped in several ways. the wood/lumber/timber industry uses two broad/generic classes or groups for the wood/lumber/timber that comes from trees, they are hardwood and softwood.hardwood comes from deciduous angiosperms which are broadleaved and are either catkin bearing or flower bearing trees. softwood comes from trees belonging to the order coniferales/coniferous gymnosperms which are cone bearing or evergreen and have needle or scale like leaves. there are exceptions! some examples would be,balsa ochroma pyramidale janka hardness 88 and basswood tilia americana janka hardness 410 are deciduous and are extremely soft.yew pacific taxus brevifolia janka hardness 1600 is in the order coniferales/coniferous and is harder than ashes fraxinus spp., birches betula spp., maples acer spp., oaks quercus spp. or walnuts juglans spp.note 2:not all species of wood/lumber/timber have had a janka hardness test performed on them and there are species that have had the janka hardness test performed on them but the results are not publicly published.note 3:because of the moisture content of wood/lumber/timber it has 2 specific gravities, the what i call density specific gravity and basic specific gravity which is also referred to as basic density. both are figured differently. all specific gravities listed on this website are density specific gravities.density specific gravity is the ratio of density of a substance compared to the density of fresh water when it is at its greatest value which is 4 degrees celsius, 39.2 degrees fahrenheit.with wood/lumber/timber to figure the density specific gravity you take the kg/m3 kilograms per cubic meter weight at 12% moisture content industry standard and divide it by 1000. that is the density specific gravity and will tell you whether the wood/lumber/timber will float or sink in water. to float in water wood/lumber/timber has to weigh less than 1,000 kg/m3.at 12% moisture content if any wood/lumber/timber had no air spaces or pockets in it, the highest possible density specific gravity it could have would be 1.52. the highest possible weight would be 1520 kilograms per cubic meter kg/m3, 3350 pounds per cubic meter m3, 94 pounds 14 ounces per cubic foot lb/ft3 or almost 5 pounds 15 ounces per board foot bf planed/dressed out 12 x 12 x 3/4 thick.basic specific gravity is calculated by oven dry mass weight divided by wet green volume and is always lower than density specific gravity. basic specific gravity is not at all accurate in telling you whether the wood/lumber/timber will float or sink in water. a few examples would be,bloodwood brosimum rubescensweight 1080 kg/m3 - density specific gravity 1.08basic specific gravity .90curupay anadenanthera colubrinaweight 1060 kg/m3 - density specific gravity 1.06basic specific gravity .86ebony gaboon diospyros crassifloraweight 1100 kg/m3 - density specific gravity 1.10basic specific gravity .83ekki lophira alataweight 1075 kg/m3 - density specific gravity 1.075basic specific gravity .87gimlet eucalyptus salubrisweight 1225 kg/m3 - density specific gravity 1.225basic specific gravity .94ipe tabebuia serratifoliaweight 1130 kg/m3 - density specific gravity 1.13basic specific gravity .91jutahy dialium guianenseweight 1089 kg/m3 - density specific gravity 1.089basic specific gravity .87katalox swartzia cubensisweight 1105 kg/m3 - density specific gravity 1.105basic specific gravity .93snakewood piratinera guianensisweight 1250 kg/m3 - density specific gravity 1.25basic specific gravity .96teak brazilian dipteryx odorataweight 1080 kg/m3 - density specific gravity 1.08basic specific gravity .86wawra combretum imberbeweight 1200 kg/m3 - density specific gravity 1.20basic specific gravity .96note 4:with wood/lumber/timber as a general rule the more it weighs, the denser it is and the higher specific gravity it has the harder it is. weight/density/specific gravity and hardness with some wood/lumber/timber species are different.wood/lumber/timber species that have more oils, gums, resins and less lignum gives hardness to wood cells in them are softer sometimes than the weight/density/specific gravity indicates they are. this is because the oil, gum and resin mixed in with the wood fibers makes the wood heavy but yet in a compression test such as janka makes the wood softer. an example would be,bauhinia red lysiphyllum carronii specific gravity 1.39 - janka hardness 4400lignum vitae guaiacum officinale specific gravity 1.35 - janka hardness 4500wood/lumber/timber species that have less oils, gums, resins and more lignum gives hardness to wood cells in them are harder sometimes than the weight/density/specific gravity indicates they are. an example would be,buloke australian allocasuarina luehmannii specific gravity 1.11 - janka hardness 5060lignum vitae guaiacum officinale specific gravity 1.35 - janka hardness 4500note 5:there are no formulas or computations to figure/convert janka hardness to specific gravity or vice versa! a particular janka hardness does not have a certain specific gravity or vice versa! an example would be,brigalow acacia harpophylla janka hardness of 2250 with a specific gravity of 1.04mahogany white eucalyptus acmenoides janka hardness of 2250 with a specific gravity of 1.01hopea heavy hopea iriana janka hardness of 2250 with a specific gravity of .92& pyinkado xylia xylocarpa janka hardness 2250 with a specific gravity of .87note 6:at the very least common/trade names can be bewildering. it is always best and if at all possible to get the botanical/scientific name of a species. each species of tree is unique and has only one botanical/scientific up to date accepted name which is recognized worldwide! for more information, see note 7.a species can have different common/trade names in different locations. an example would be the botanical/scientific name of hyeronima alchorneoides with a janka hardness of 1700. it has the common/trade names of,bully tree woodnancitonnogal nicoyanpilonrositasuradanzapaterothe same common/trade name can be given to more than one wood/lumber/timber species either having a completely different genus the first name in a botanical/scientific name or having the same genus but a different species name the second name in a botanical/scientific name. an example having a completely different genus would be, botanical/scientific name astronium graveolens with a janka hardness of 2160 & botanical/scientific name lovoa trichilioides with a janka hardness of 940. both are sold by the common/trade name of tigerwood.an example having the same genus but a different species name would be, botanical/scientific name peltogyne paniculata with a janka hardness of 2710, botanical/scientific name peltogyne porphyrocardia with a janka hardness of 2430 & botanical/scientific name peltogyne venosa with a janka hardness of 2030. although all three are somewhat different in color, weight and janka hardness, they are sold by the common/trade name of purpleheart.sometimes the wood flooring industry gives their own made up common/trades names to the wood/lumber/timber species they sell as flooring. examples would be,ash brazilian apuleia leiocarpa janka hardness of 1660cherry andean guibourtia chodatianal janka hardness of 2800cherry caribbean lonchocarpus castilloi janka hardness of 2700cherry patagonian guibourtia chodatianal janka hardness of 2800chestnut patagonian cabralea parda janka hardness of 1610mahogany andean anadenanthera colubrina janka hardness of 3840maple patagonian balfourodendron, riedelianum janka hardness of 1500rosewood tiete guibourtia chodatianal janka hardness of 2800rosewood patagonian anadenanthera colubrina janka hardness of 3840walnut caribbean lysiloma bahamensis janka hardness of 1400walnut patagonian tabebuia heptaphylla janka hardness of 2800.some common/trade names can indicate that a wood/lumber/timber species belongs to a certain group genus when actually it is not even a member of that group genus. examples would be,common/trade name ebony mexican. it is not genuine ebony, genus diospyros it is genus swartziacommon/trade name mahogany santos. it is not genuine mahogany, genus swietenia it is genus myroxyloncommon/trade name pine klinki. it is not genuine pine, genus pinus it is genus araucariacommon/trade name rosewood bolivian. it is not genuine rosewood, genus dalbergia it is genus machaeriumcommon/trade name walnut african. it is not genuine walnut, genus juglans it is genus lovoanote 7:botanical/scientific names can and do change. ongoing study of a tree may show the tree to have been wrongly classified and with new information be reclassified in a different family, genus or species. to change a trees botanical/scientific name is not easy. the rules are set forth by the international code of nomenclature for cultivated plants, icncp.a tree may have had other botanical/scientific names over the years, but only one name is the up to date accepted name. the previous old outdated names are called synonyms. botanical/scientific name synonyms are not interchangeable like the standard usage of the word synonym. botanical/scientific name synonyms are not to be used as a substitute for the up to date accepted name! of course the old outdated names may stay around for years because people do not keep up with the name changes. examples would be,the wood/lumber of sheoak forest, with the janka hardness of 3150 has the up to date accepted botanical/scientific name of allocasuarina torulosa.it has the synonym botanical/scientific name ofcasuarina torulosa.the wood/lumber of louro vermelho, with the janka hardness of 660 has the up to date accepted botanical/scientific name of sextonia rubra.it has the synonym botanical/scientific names ofnectandra rubraocotea rubrathe wood/lumber of, kapok with the janka hardness of 240 has the up to date accepted botanical/scientific name of ceiba pentandra.it has the synonym botanical/scientific names ofceiba guineensisbombax pentandrumeriodendron caribaeumthe wood/lumber of the brazilian fire tree, with the janka hardness of 450 has the up to date accepted botanical/scientific name of schizolobium parahybum.it has the synonym botanical/scientific names ofcaesalpinia parahybacassia parahybaschizolobium excelsumschizolobium parahybathe wood/lumber of ebony texas, with the janka hardness of 2570 has the up to date accepted botanical/scientific name of ebenopsis ebano.it has the synonym botanical/scientific names ofacacia flexicaulischloroleucon eban